help

I'm very new to motorized biking, having just finished turning an old 90's mountain bike into a speed demon. (or at least I hope it will be) The kit I got was a pretty standard 49cc 4 stroke from ebay. The biggest problem I've had so far is the chain that connects the belt drive to the sprocket...

So I have set the engine onto the mountain bike have checked the spark plug for spark and I do get spark when tested on the outside case. I can get the engine started when I peddle to 20km/h but it wont idle and The throttle needs to be full throttle. If I start at a lower speed I get...

hey guys, so my first build i ran it and the engine idled flawlessly. For a while, then the bike would no longer idle. When I pull the clutch the RPMS shoot sky high. When I leave the clutch it’s always trying to go like a car placed in “drive”. Any ideas? Thanks guys!

HEY GUYS! Just built my first beauty. It’s running well and strong aside from when I picked up a nail. However I have a question about how you guys like to secure your gas tank and mufflers. My attached components are tending to vibrate loose. Am I just going too fast? Or if there another way to...

So this is my first build, and once it was all together, I found that on disengaging the clutch the bike would not roll but what little slack the chain would allow before the chain would run out of play and snag. I’ve gone through clutch re-set and cleaning procedures, such as cleaning the pad...

So, my 80cc 2 stroke motorized bicycle bike runs normally for 7-10 minutes but then it starts to jerk and the thing starts to shut off and can't turn back on. (it feels like gas isn't going through properly) But then a day later, it worked again! but the same problem happened!! HELP

Hi y'all, new to the forum thing in general, I've got a 2 stroke grubee Skyhawk that I rebuild mostly with a Chinese clone. The clone I ran for about 30 miles but decided it would be better for parts considering the head and cylinder were one piece (ofc the seller online didn't show that). And...

I need help building a bike. I read that the DIY kits aren't very good. I dont have crazy money I'm trying to do this as cheap as I can but also have a quality set up. I live in the mountains but i wont be riding up and down actual mountains but there are alot of hills to deal with .I want to...

I have a problem in my clutch and I do not know what type and version it is, I need to know to buy a new one, could someone help me find out what it is? I only know that my engine is 4-stroke

Hello, I'm trying to install an engine kit on my Mongoose Excursion 27.5". This bike is 21 speed, and has this assembly on the back of the bike. In order for this engine kit to work, it needs to have one large gear on the pedals, and the shifter on the back wheel needs to go. I was wondering...

Hello, I'm trying to install an engine kit on my Mongoose Excursion 27.5". This bike is 21 speed, and has this assembly on the back of the bike. In order for this engine kit to work, it needs to have one large gear on the pedals, and the shifter on the back wheel needs to go. I was wondering...

Ok so I'm new to this but have been repairing and tinkering with stuff for years and I'd say I'm mechanically inclined. Picked up this kit, originally meant for a frame mount, from a guy on Craigslist for $80. I am trying to figure out which make/model kit I have here, any pro's & cons of this...

Hey guys I have a red lion 2Ralg 79cc 4 stroke and the crankshaft seems to be 5/8 without a keyway, I really need a 3/4 in shaft q type. Any suggestions?

I've had this bike for about 5 months now and it been a nightmare, it has compression has spark and I don't know why it's not starting, it turns over but doesn't start. Help?:-||

Hello guys! First - Thank you for taking the time to read my post. I need some help finding an engine to buy. So I have a small (seven months) experience with an chinese engine I brought off e-bay. Actually i knew that the engine probably wont be the best quality, but i just wanted to first try...

First time on this site as a member, but I've built one of these 66cc bikes before, now i'm addicted and want to go further. I want to use a 420 predator to make an actual 50mph motorcycle. My question is this: Where can I find a small (minimum 3 speed) transmission that can take up to 20 hp...

Ok, so these last few weeks I've had the urge to make a light trail/offroad bike. I would like to add much more low end power. So my list is: Port my cylinder for low end power Extend header on my expansion chamber go back to 44 tooth sprocket What else do I need for this and Can anyone help...

I recently went on a 2-3 mile trip on my bike, just riding around with a friend. I dropped my allen key set, went to go pick it up, and and soon as I picked it up my bike shut off. Since then, I haven't been able to get it to start. I drained all the fuel, put new gas in, replaced the...

Hi guys my name is Luca and I was wondering what kit I should get for the 66cc 2 stroke engine kit. I live in canada Also there are so many kits like I am truly confused on which one to buy any suggestions. My budget is about 200 cad or 160 us on the kit. Also which bike should I get I don't...

Here's what I got. This thing never ran right from day 1 and I'm tired of it. Do I spend the money on a jet kit or is there a carb I can buy that would be as big as the keihin that will actually work? I finally have my low end rpm smooth and powerful, but when cracking wide open after that...